Hello Charlie, You will notice that a number of items including the t-shirts are listed with a description as "SLIM FIT" and you will also notice that there are half chest measurement sizes in brackets next to each item to give you an idea of the size of the item so that you can keep this in mind and use these measurements when choosing an item. The descriptions and half-chest measurement sizes are provided by the shirt manufacturers. FYI - recently I bought a male "slim fit" XL shirt from Hallensteins and this was definitely different to a "regular fit" XL.